Lightning-arrester



SSheets-fiheet 1.

(No Model.)

P. 0. K'EILHOLTZ.

LIGHTNING ARRESTER.

No. 384.042. Patented June 5, 1888.

INVENTOR WITNESSES. {I @We 06? @mwg (Q 7%.

ttorne (No Model.) 3 Sheets-Sheet 2.

P. O. KEILHOLTZ.

LIGHTNING ARRESTER. No. 884,042. Patented June 5, 1888.

, WITNESSES VENTOR. 1 5, 4 6 w 7 I X4 8 W, W W I ACO flttorney I UNITEDSTATES PATENT OFFICE.

PIERRE OTIS KEILHOLTZ, OF BALTIMORE, MARYLAND.

LlGHTNING-ARRESTER.

EFPEGCIPIGATION forming part of Letters Patent No. 384,042, date-cl Jane5, 1888.

Serial No. 263.330. (N0 model.)

To (ZZZ whom it may concern.-

BeitknownthatLPInnRE OTIS KEILHOLTZ, a citizen of the United States, anda resident of the city of Baltimore, in the State of Maryland, haveinvented certain new and useful Improvements in Lightning-Arresters, ofwhich the following a full, clear, and exact specification, referencebeing had to the accompanying drawings.

My invention relates to that class of lightning-arrestcrs which are usedupon electriclight circuits. Its purpose is to relieve the line and theapparatus included in the circuit from the destructive effect of largetransient currents--such as are due to lightning-by providing a means ofescape for such currents from the line without injury to the apparatus.To accomplish this result, I make use of the fact that anelectro-inagnet, on account of' its self-induction, offers a greatresistance to the passage of transient currents. The electromagnet Iemploy as a dam to divert the current from itself to ashnnt, which,having little or no self induction, will permit the transient currentsto flow through it and thence to ground. v

In the drawings, Figure 1 is a perspective view of my apparatus. Fig. 2is a plan of the same. Fig. 3 is the side elevation showing the leverdrawn back by the armature. Fig. i is a diagram showing the main line,branch, and electrical connection of the lightning arrester apparatus.Fig. 5 is a perspective view of my apparatus,showing a form of shuntthat is desirable for some purposes composed of a pile of carbon disks.

Similar letters of reference indicate similar parts in all the figures.

A represents an electro magnet; a, a core or armature suspended upon theinterior of the elect ro-n'iagnct; B, a shuntwhich may be made in anyot'sevcral ways.

The drawings, Fig. 4, represent a carbon rod sustained by a holder ofconducting material and resting upon a metal plate. Another formol'shunt which gives good results,beeause having less sell-induction, isa pile of small carbon disks laid one on top of the other, connected atone end with a line and the other with the arrester, which is inelectrical connection with the earth.

On the top of the elcctro magnet there is a metal plate, 0, with whichthe holder of the shunt is in electrical contact. Upon this plate 0 aretwo standards, 0 c, in which is journalcd ashait, 0*. Upon the shaft 0is mounted a disk or pulley, c. To the shait a" is secured in aperpendicular position alevcr, D, the end of which is provided with apoint, cl". (2* is another lever attached to sa. shaft and extending inan opposite direction from the lever D, and is provided with acounterbalanceweight, (1 Opposite the point cl, but disconnected from itand mounted upon a standard, is a metal plate or point, E. This plate isin electrical connection with the earth. Over the disk 0 passes acord,0, which is secured to the core (L at one end and to a spring, 0 at theother. The purpose of said spring a is to restore the lever D to itsnormal position when the clectro-x'nagnet ceases to attract the core a.

F is the main line, and f a single branch. The branch f is divided intotwo parts-f and f one of which is connected with the electro magnet andthe other with the shunt.

The electrical connection through the electro-magnet when dischargetakes place is as follows: Line F, branch branch f to electromagnet A,through coils, plate 6, standard 0 0, shaft 0' lever 1), point d throughthe airspace, plate E, to earth. The connection through the shunt wherethe discharge takes place is as follows: Line F, branch f, branch fshunt B, plate G, standard 0 0, a shaft, 0 lever D, point (1 through theair-space or dielectric, plate E, to earth.

The plate E is provided with an offsetting stop, 0, arranged to preventthe point (2 of the lever D from coming in contact with the plate E andto retain said point at a definite distance from the plate. Thisdistance of the point from the plate is arranged to be of such a lengththat the normal potential or electromotive force of the line will not beable to overcome the resistance of the intervening airspace, so that itwill constitute a complete break in the earthconnection.

The operation of the device is as follows: W'hen a large transientcurrent passes over the line F, it will flow into the branch thence willdivide itself between the branch j' f but as it passes into the coil ofthe electro-magnet the self-induction of the coil will resist its flowand act as a dam, so as to divert the whole or nearly the wholetransient current to the shunt, through which it will pass, thence tothe lever D and point d, where it will jump the air-space between thepoint d and plate E, forming an arc, and thence escape to the earth. Theare thus created will be maintained by the flow of the normalline-current, if a ground exists somewhere else on the line in such aposition as to maintain it, and in order to prevent the continued escapeof the normal line-eurrent it is necessary to destroy this are. This isdone by the action of the elcctro-magnet upon the core a. After thetransient current has passed the normal line-current continues to flow.The shunt is made of higher resistance than the coil; hence the greaterpart of the line-current will pass through the coil instead of theshunt. As a result the armature will be attracted and drawn into thecoil, the disk will be turned by the action of the cord which passesover it, the lever D will be drawn backward, and the are destroyed. Assoon as the ground-connection is broken, the current ceases to flow andthe electro-magnet is demagnetized, releasing its armature, and theretractile spring 0 draws the armature up and returns the lever D to itsnormal position.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, 1s

1. In a lightning-arrester for electric lines, the combination of a mainline with a branch from said line and a ground connection separated fromsaid branch by a small air-space or other dielectric with anelectro-magnet of high self-induction but low ohmic resistance, and ashunt of low self-induction but high ohmic resistance, each included ina divisional branch of the main-line branch, said divisional branchesreuniting before reaching the dielectrio, and means operated by theelectro-magnet for breaking the ground-connection automatically after ithas been established by an arc bridging the dielectric, substantially asdescribed.

2. In a lightning-arrester apparatus for electric'light lines, thecombination of a main line with a branch from said line and agroundconnection separated from said branch by a small air-space orother dielectric with an electro-magnet of high self-induction but lowohmic resistance, which is provided with an armature, and a shunt of lowself-induction but high ohmic resistance, each included in a divisionalbranch of the mainline branch.

PIERRE OTIS KEILHOLTZ,

Attost:

GEO. W. 1100mm, 0. H. SADTLER.

